How To Make A High-Tech Spy Stethoscope

Hear through walls with this high-tech spy stethoscope for under $25.

Step 1: Definition

A stethoscope is often seen as a symbol of a doctor's profession. it can also be used by safe-crackers and auto mechanics to hear sounds that otherwise could not be heard. Well, it's time to make a high-tech electronic spy stethoscope for under $25.

We'll be using a stethoscope, which I picked up at a local drugstore and a pair of multimedia microphones.

Step 2: Un-assemble

I carefully un-assembled the microphones and ended up with two mini condensor microphones and 3 1/2 millimeter mini stereo plugs. I was surprised that the specs on these microphones are actually quite good.

Then, I removed the earpieces from the stethoscope and drilled them out to match the microphone housings.

Step 3: Re-assemble

After some fine-tuning and a little hot glue, I reassembled the ear pieces and reassembled them on to the stethoscope.

I plugged these ear pieces into a mini stereo Y adapter, and then into my MP3 player and I got ready to record what I heard.

Step 4: Results

I was amazed at the clarity of this spy stethoscope and now, instead of a regular stethoscope, I could actually record what I heard.

I heard my wife on the telephone and decided to test it out on a wall.